For your viewing pleasure today is a 13-way AMD Radeon graphics card comparison
when testing out the open-source Radeon Gallium3D drivers on the wide spectrum
of ATI/AMD GPUs while looking at the performance for Valve's Source Engine with
Counter-Strike: Source and Team Fortress 2. Given the imminent arrival of Steam
Machines and SteamOS to push Linux gaming into its long-awaited spotlight, is
AMD's open-source Linux graphics driver capable of delivering a reasonable level
of performance?

From Ubuntu 13.10, the open-source driver configuration tested was the current
best experience possible using the Linux
3.12 kernel (and enabling Radeon Dynamic Power Management; it will be defaulted
in Linux 3.13) and using the Mesa
10.0 Gallium3D code that's expected to be released as stable later in the
month. For those curious how the open-source Radeon performance compares to the
closed-source Catalyst driver for Valve's Source Engine games, that comparison
will be saved for a later article on Phoronix. This article is just looking at
the open-source AMD Radeon driver performance and not Catalyst since this testing
goes back further than the HD 5000 series where the current mainline Catalyst
driver support ends. The Legacy Catalyst driver for HD 2000/3000/4000 series GPUs
is not compatible with modern Linux distribution releases due to kernel and xorg-server
compatibility problems.

Originally, this was going to be an open-source Linux GPU driver comparison
of not just AMD Radeon graphics processors but also NVIDIA GPUs with the open-source
reverse-engineered Nouveau driver. However, the current Nouveau Gallium3D driver
doesn't really work properly for Source Engine, at least when tested with Team
Fortress 2 and Counter-Strike Source. I've tried Nouveau on multiple systems but
it is always a miserable mess for Source (screenshots below). The lack of re-clocking support so the
GPUs core and memory frequencies can properly be set for modern GPUs also makes
its performance horrible compared
to NVIDIA's official Linux driver. The binary NVIDIA driver works wonderfully
for the Source Engine on Linux and I had shared some 10-Way
NVIDIA TF2 benchmarks a few days earlier.